Mechanical method and apparatus for bilateral tissue fastening

ABSTRACT

A mechanical system for bilaterally securing skin tissue preferably utilizes a tissue manipulator apparatus to approximate a portion of an interior surface of each of two pieces of living dermis tissue along a vertical interface below an exterior surface without overlapping either interior surface across the vertical interface. An applicator apparatus includes a driving head portion positioned in the vertical interface and at least partially below the exterior surface and a handle portion positioned at least partially above the exterior surface. The applicator apparatus bilaterally drives at least one portion of the fastener through each piece of the living dermis tissue behind the interior surface of that piece of tissue such that the fastener is positioned below the exterior surface and a portion of the fastener is positioned generally transverse to the vertical interface.

FIELD OF THE INVENTION

The present invention relates generally to the field of surgicalinstruments such as surgical staplers, clip applicators and suturelessclosure devices. More particularly, the present invention relates to amechanical method and apparatus for fastening tissue, such as skintissue, with a fastener positioned below the tissue surface thatbilaterally secures opposed pieces of tissue.

BACKGROUND OF THE INVENTION

When an opening in tissue is created either through an intentionalincision or an accidental wound or laceration, biological healing of theopening commences through the proximity of the opposed living tissuesurfaces. If the opening is very large or if its location subjects thewound to continual movement, a physician will seek to forcibly hold thesides of the opening in close proximity so as to promote the healingprocess.

In the case of skin tissue, for example, healing occurs best when theopposing dermal layers of the skin tissue are held in proximity witheach other. Human skin tissue is comprised of three distinct layers oftissue. The epidermal layer, also known as the epidermis, is theoutermost layer and includes non-living tissue cells. The dermal layer,or dermis, is the middle layer directly below the epidermal layer andcomprises the living tissue of the skin that is the strongest of thethree layers. The subcutaneous, or hypodermis layer is the bottom layerof skin tissue and includes less connective tissue making this theweakest layer of skin tissue.

The most prevalent method for forcibly closing a tissue opening isthrough the use of a suture or “stitches.” As early as the secondcentury, the Greeks were using sutures to physically close skinopenings. In its simplest form, a suture is simply a length of materialthat is attached to a tissue-piercing device, such as a needle, andlooped through the opposing sides of an opening. The suture is thenpulled tight and the loop closes causing the opposing sides of thetissue to come into close physical proximity. The suture loop is heldtight by the tying of a knot or some other locking mechanism. The firstsutures were made of animal gut. Eventually other natural suturematerials including leather, horsehair, flax, cotton and silk came intouse.

As the sciences of medical and materials technology have advanced overthe course of the past century, new bioabsorbable materials have beendeveloped to further improve upon the basic suturing concept. Examplesof modem improvements to the suturing process include enhancements tothe suturing apparatus as shown, for example, in U.S. Pat. Nos.2,439,383, 2,959,172 and 3,344,790, as well as advances in sutures andsuture materials as shown, for example, in U.S. Pat. Nos. 3,123,077,3,297,033, 3,636,956, 3,792,010 4,027,676 and 4,047,533.

While traditional suturing remains a popular method of effectuatingclosure of skin openings, the use of staples and staplers as a skinclosure technique has become increasingly popular, especially insurgical settings where the opening is created through a purposefulincision. In these settings, the incision tends to make a clean,straight cut with the opposing sides of the incision having consistentand non-jagged surfaces. Typically, stapling of a skin opening, forexample, is accomplished by manually approximating the opposing sides ofthe skin opening and then positioning the stapler so that a staple willspan the opening. The stapler is then manipulated such that the stapleis driven into the skin with one leg being driven into each side of theskin and the cross-member of the staple extending across the openingexternal to the skin surface. Generally, the legs of the staple aredriven into an anvil causing the staple to deform so as to retain theskin tissue in a compressed manner within the staple. This process canbe repeated along the length of the opening such that the entireincision is held closed during the healing process.

Much work has been devoted to improving upon the basic stapling process.Developments have gone in a variety of directions and include workdevoted to the stapling apparatus as shown, for example, in U.S. Pat.Nos. 3,082,426, 3,643,851, 4,410,125, 4,493,322, 4,592,498, 4,618,086,4,776,506, 4,915,100, 5,044,540, 5,129,570, 5,285,944, 5,392,979,5,489,058, 5,551,622, 5,662,258, 5,794,834, 5,816,471, 6,131,789 and6,250,532. In addition to the stapling apparatus, developments have alsobeen made in the staple design as shown, for example, in U.S. Pat. Nos.2,351,608, 2,526,902, 2,881,762, 3,757,629, 4,014,492, 4,261,244,4,317,451, 4,407,286, 4,428,376, 4,485,816, 4,505,273, 4,526,174,4,570,623, 4,719,917, 4,741,337, 5,007,921, 5,158,567, 5,258,009,5,297,714, 5,324,307, 5,413,584, 5,505,363 and 5,571,285.

While modern suturing and stapling techniques continue to provide aneffective manner of effectuating skin closure, there remains a series ofinherent disadvantages in using either of these techniques. The standardtechnique for both suturing and stapling includes puncturing both theepidermis and dermis. This can result in a wound closure having anunaesthetically pleasing appearance on the surface of the skin. Thepresence of the fastener exposed through the skin surface provides anopportunity for infection and for accidentally catching the fastener andtearing the wound open. In the case of non-absorbable fasteners, furtheraction by a medical professional is necessary in order to remove thefastener once biological healing is complete.

In order to overcome these limitations, practitioners have developed anumber of specialized suturing techniques where the suture is passedonly through the dermis effectively positioning the suture below theskin surface, or in a subcuticular fashion. A surgeon has the choice ofplacing individual or interrupted sutures along the length of anopening. Another suturing option is for the surgeon to use a singlestrand of suture material to place a plurality of continuing sutureloops or running sutures along the length of an opening. While thepresence of the suture below the surface can improve the aestheticnature of the closure, it requires greater skill and technique toaccomplish effectively and takes longer than conventional externalsuturing.

While there has been active development of dermal layer suturingtechniques, little has been done in the area of staples and staplers foruse in connection with the dermal layer. In a series of patents issuedto Green et al., including U.S. Pat. Nos. 5,292,326, 5,389,102,5,489,287 and 5,573,541, a subcuticular stapling method and apparatusare disclosed that were ultimately commercialized as the US Surgical SQSSubcuticular Stapling Apparatus. The Green et al. patents describe astapling technique employing a handheld apparatus with jaws toproximate, interdigitate and overlap opposing sides of dermal layertissue along the length of a skin opening. The apparatus then drives asingle spike through the interdigitated and overlapped dermal layers ofthe opposing skin surfaces in order to secure both sides of the dermaltissue on the single spike. Although this technique reduced the timerequired to effectuate a subcuticular skin closure, the SQS device wasnot commercially successful in part because the resulting closureproduced an undesirable wave-like scar that sometimes did not healeffectively.

While many improvements have been made to mechanical tissue closuretechniques, it would be desirable to provide a mechanical tissue closuresystem that is capable of effectively delivering fasteners below theskin surface so as to produce an efficient and efficacious tissueclosure.

SUMMARY OF THE INVENTION

The present invention is a mechanical system for bilaterally securingskin tissue. Preferably, a tissue manipulator is used to approximate aportion of an interior surface of each of two pieces of living dermistissue along a vertical interface below an exterior surface withoutoverlapping either interior surface across the vertical interface. Anapplicator apparatus includes a driving head portion positioned in thevertical interface and at least partially below the exterior surface,and a handle portion positioned at least partially above the exteriorsurface. The applicator apparatus bilaterally drives at least oneportion of the fastener through each piece of the living dermis tissuebehind the interior surface of that piece of tissue such that thefastener is positioned below the exterior surface and a portion of thefastener is positioned generally transverse to the vertical interface.

Unlike existing mechanical tissue fastening systems, the presentinvention recognizes the need for and advantages of a fastener systemthat captures and retains dermal tissue in a compressed state within apreferably bioabsorbable fastener that is not inserted through theepidermal skin layer. The mechanical fastening system of the presentinvention is able to consistently and repeatedly interface a fastenerwith a target tissue zone in the dermal layer such that the fastenerinserted into the target tissue zone produces an effective andaesthetically pleasing closure of a tissue opening.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a typical opening in skin tissue such as may be closed bythe present invention.

FIG. 2 shows a cross-sectional view of the skin tissue and opening ofFIG. 1.

FIG. 3 shows a cross-sectional view of everted skin tissue.

FIG. 4 shows a perspective cross-sectional view of an opening in skintissue at rest, indicating optimal bilateral target tissue zones.

FIG. 5 shows an enlarged view of a target tissue zone.

FIG. 6 shows the view of FIG. 4 with the skin tissue everted.

FIG. 7 is a perspective view of a currently most preferred embodiment ofthe applicator apparatus of the present invention.

FIG. 8 is a perspective view of the lower handle and driving headportions of the applicator apparatus of FIG. 7.

FIG. 9 is a top plan view of the lower handle and driving head portionsof the applicator apparatus of FIG. 7.

FIG. 10 is a partial cross-sectional view of the driving head portionshown in FIG. 9.

FIG. 11 is a side elevation view of the lower handle and driving headportions of the applicator apparatus of FIG. 7.

FIG. 12 is a perspective view of the lower handle and driving headportions as depicted in FIG. 8 with a fastener positioned therein.

FIG. 13 is another perspective view of the lower handle and driving headportions as depicted in FIG. 8 with a fastener positioned therein.

FIG. 14 is a phantom view of the applicator apparatus of a currentlymost preferred embodiment of the present invention having an automatedfastener delivery and storage mechanism.

FIG. 15 is an enlarged phantom view of the apparatus of FIG. 14.

FIG. 16 is a partial view of the apparatus of FIG. 14.

FIG. 17 is a perspective view of a currently most preferred embodimentof a manipulator apparatus according to the present invention.

FIG. 18 is an enlarged view of the jaw portions of the manipulatorapparatus of FIG. 17.

FIG. 19 is a perspective view of a currently most preferred embodimentof a fastener according to the present invention.

FIG. 20 is a top plan view of the fastener depicted in FIG. 19.

FIG. 21 is a perspective view showing the orientation of applicator andmanipulator apparatus during a step of a currently most preferredembodiment of the method of the present invention.

FIG. 22 is a perspective view of the apparatus during another step ofthe method of the present invention.

FIG. 23 is a perspective view of the apparatus during yet another stepof the method of the present invention.

FIG. 24 is a perspective view of the apparatus during still another stepof the method of the present invention.

FIG. 25 is a top plan view of an alternative embodiment of a fasteneraccording to the present invention.

FIG. 26 is a side elevation view of the fastener of FIG. 25.

FIG. 27 is a view of the fastener of FIG. 25 in a deployed condition.

FIG. 28 is a view of an applicator assembly according to an alternativeembodiment of the invention.

FIG. 29 is another view of an applicator assembly according to analternative embodiment of the invention.

FIG. 30 is a pictorial representation of a skin opening closed withconventional subcutaneous sutures.

FIG. 31 is a pictorial representation of a skin opening closed byconventional surgical stapling.

FIG. 32 is a pictorial representation of an opening closed with theprior art interdigitated subcuticular stapler.

FIG. 33 is a pictorial representation of an opening closed using thebilateral fastening technique of the present invention.

FIG. 34 is a longitudinal cross-sectional view of an alternativeembodiment of the present invention showing operation of correspondingguiding features on the tissue manipulator and the applicator.

FIG. 35 is a longitudinal cross-sectional view of an alternativeembodiment of the present invention showing ball tip ends on the tissuemanipulator and corresponding semi-spherical areas on the applicator.

FIG. 36 is a top cross-sectional view of the alternative embodimentshown in FIG. 35.

FIG. 37 is an isometric view of an alternate embodiment of theapplicator assembly in which the fasteners are inserted obliquely intothe tissue.

FIG. 38 is an isometric view of an alternate embodiment of the presentinvention in which the tissue manipulator and the applicator assemblyare incorporated in a single handheld instrument.

FIG. 39 is a plan view of a preferred embodiment of a fastener showingthe inner cross-sectional area.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In FIGS. 1-3 there is shown a depiction of a typical opening 50 in thesurface of skin 52, such as may be made, for example, by a surgicalincision or a wound. As illustrated in FIG. 1, for purposes ofdescribing the present invention, opening 50 may be described as havinga length or longitudinal orientation parallel to the y-y axis, a widthorientation parallel to the x-x axis, and a depth orientation parallelto the z-z axis. The x-y-z axis for purposes of the present invention isdefined with respect to an external tissue surface, which in the case ofskin 52 is the outer surface. References to a vertical and horizontalplanar orientation in connection with the present invention are madewith respect to the external tissue surface at the site of the openingin question. The vertical inner surfaces 60 formed by each side of theopening 50 can be visualized as meeting along a generally verticalinterface 51. It will be understood that in the case of an opening thatextends over a curved tissue surface, the corresponding horizontal andvertical surfaces associated with the opening will be defined withrespect to such curved tissue surface. It also will be understood thatthe vertical interface 51 may be vertical in only one orientation withrespect to the tissue surface, such as in the case when an angledincision has formed the opening 50.

As is best illustrated in the sectional views of FIGS. 2 and 3, humanskin 52 generally has three discrete layers. These layers comprise anepidermal layer 54 of mostly non-living tissue having an exteriorsurface 55, a dermal layer 56 of mostly living tissue, and asubcutaneous tissue layer 58. Although the preferred embodiment of thepresent invention will be described with respect to human skin tissue52, it will be understood that the present invention is applicable toclosure of openings in other types of tissue having generally definedsurfaces, such as fascia, membranes organs, vessels, vasculature,vascular pedicles, skin grafts, bladder and other biocompatiblematerials with generally defined surfaces such as artificial skin,artificial membranes and synthetic mesh.

It has long been known that the most rapid healing of a skin openingwith a minimum of scarring occurs when the inner surfaces 60 of theliving dermal layer 56 at each side of the vertical interface 51 of skinopening 50 are brought together and held in close contact in what isreferred to as an everted position as is shown in exaggerated fashion inFIG. 3. To the extent that the primarily non-living material ofepidermal layer 54 can be excluded from the healing opening, therapidity and level of scar tissue formed during the healing process willbe improved.

The ability of the present invention to provide a more effective andefficacious tissue closure can be seen with reference to FIGS. 30-33,which show skin openings closed by various prior art methods as comparedwith an opening closed using the bilateral fastening techniques of thepresent invention. In FIG. 30, there is shown a skin opening closed withsubcutaneous sutures. The generally everted condition of the closedopening can produce unattractive scarring and less than optimal healingif the eversion is excessive or inadequate. As can be seen from FIG. 30,obtaining consistency from suture to suture is difficult and the qualityof the closure is highly dependent upon the skill of the surgeon. FIG.31 shows a skin opening closed by conventional surgical stapling. Inaddition to the generally unattractive appearance of the closed opening,staple openings and the excessive everted condition of the opening maylead to undesirable scarring. In addition, if non-resorbable staples areused, the staples must be removed before complete healing can occur.FIG. 32 shows a depiction of an opening closed with the interdigitatedsubcuticular stapler known as the SQS device that is described, forexample, in U.S. Pat. Nos. 5,292,326, 5,389,102, 5,489,287 and5,573,541. The characteristic undulating appearance caused by theoverlapping interdigitation of the skin may lead to an unusual appearingscar in the healed opening. The overlapping and interdigitation of theskin can also cause epidermis tissue to be interposed between dermallayers, thereby leading to incomplete healing or excessive scarring.

By comparison, an opening that has been partially closed by the methodand using the apparatus of the present invention is shown in FIG. 33. Asshown, the closed portion of the opening is tightly closed, yet liesflat without undue eversion of the opening leading to better healingperformance with minimal scarring. There is consistency in the closurefrom fastener to fastener. Because the fasteners are positioned belowthe skin surface (i.e., subcuticular), the fasteners are not exposed andthere is no puncturing or button holing of the epidermis that can leadto the increased possibility of infection or interference with thenormal healing process. In addition, if fasteners made of abioresorbable, bioabsorbable or even a bioerodible material are used,there is no need to later remove the fasteners.

The advantages of the present invention are accomplished by an apparatusand method that bilaterally engages target tissue zones 70 on each sideof a skin opening 50 with a fastener that is preferably made of abioresorbable material. As used in connection with the presentinvention, the term bilateral refers to at least two axis of insertionfor a fastener that are on separate sides of the vertical interface 51of an opening 50. The bilateral engagement may be made eithersimultaneously or sequentially, and the fastener used may have a varietyof configurations and be oriented in a variety of ways as will befurther described herein. The location, geometry and orientation of thefastener and the dermal layers in relation to the mechanical apparatusof the present invention are all important considerations to obtainingthe most optimal contact and compression of the dermal layer forefficacious closing of the opening. While the skin opening 50 will bedescribed in connection with an opening in a single piece of tissue, itwill be understood that the opening 50 could also be between twoseparate and otherwise unconnected pieces of tissue, or even between apiece of tissue and a piece of biocompatible material to be secured tothat piece of tissue.

As is shown in FIGS. 4 and 5, there exists an optimal target tissue zone70 on each side of vertical interface 51 that may be bilaterally engagedby a fastener in order to achieve optimal dermal contact for healing.This target tissue zone 70 lies within the dermal layer 56, and can bevisualized as a rectangular cross-sectional area when the tissue is in arelaxed condition as shown best in FIG. 4. In addition, within targettissue zone 70, there exists a most preferred area 72 for tissueengagement. In the depth orientation, target tissue zone 70 lays betweena distance L3 of about 0.1 mm below the surface 55 of epidermal layer54, and a distance L4 up to 2.0 mm below the surface 55. The mostpreferred area 72 lies between a distance L5 of about 0.2 mm and adistance L6 of about 0.8 mm below the surface. In the width orientation,target tissue zone 70 lies between a distance L7 of about 1.0 mm and adistance L8 of about 20.0 mm from vertical interface 51. Most preferredarea 72 lies between a distance L9 of about 2.0 mm and a distance ofabout 8.0 mm from vertical interface 51. Because the target tissue zone70 is not visible to an operator, the manipulator assembly 400 andapplicator assembly 100 are preferably designed to consistently andrepeatedly enable the operator to position the target tissue zone 70 fordeployment of a fastener 400.

As illustrated in FIG. 6, due to the inherent flexibility and resilienceof skin tissue, it is most desirable that a fastener 400 be deployedinto the target tissue zone 70 while the skin opening is everted. Bycompressing the everted dermal layers 56 on either side of the opening50 into the fastener 400, the dermal layers 56 are retained in closecontact with each other by the fastener 400 after the everting pressureis removed and the skin relaxes into a flat condition as shown in FIG.4.

A preferred embodiment of the apparatus of the present invention isshown in FIGS. 7-20. Generally, the apparatus includes an applicatorassembly 100, a tissue manipulator assembly 300, and a fastener 400.

A preferred embodiment of applicator assembly 100 is shown in FIGS.7-16. The assembly generally comprises upper handle portion 110 andlower handle portion 120, to which is attached driving head 140. Trigger200, which pivots about pivot 202 is provided to allow user actuation ofthe mechanism. Although a manual pivoting trigger arrangement 200 isshown, it will be understood that a variety of other user-actuatedmanual triggers, buttons or actuator mechanisms may be utilized with theapplicator assembly 100, such as a push button, slide mechanism, cammechanism, spring actuated apparatus, cable actuated pull mechanism,rotating mechanism or tab actuated trigger. Alternatively, an automaticactuator in the form of an electronic, pneumatic, motion controlled,remote controlled or computer-activated trigger may be used to operatethe applicator 100.

In FIGS. 8-13, there are shown detailed views of a preferred embodimentof a driving head 140 and lower handle portion 120. Driving head 140 ispreferably U-shaped and has an anvil portion 142 separated from backingportion 144 by a cross-member 146, thereby forming a gap 148.Cross-member 146 preferably has concave areas 150, which are shaped tocorrespond to tissue manipulator surfaces 318 of tissue manipulatorassembly 300, allowing the dermal layer 56 of skin to be compressed intocontact within gap 148, and with target tissue zones 70 present forcapture on either side of vertical interface 51 as will be furtherexplained hereinbelow. Although driving head 140 is shown in a fixedorientation relative to lower handle portion 120 and upper handleportion 110, it will be understood that driving head 140 may bearticulated, either in the plane of the vertical interface 51 orperpendicular to the plane of the vertical interface 51, to allow forincreased maneuverability and orientation of driving head 140.Alternatively, lower handle portion 120 may be articulated relative toupper handle portion 110, or both lower handle portion 120 and drivinghead 140 may be articulated.

Preferably, anvil portion 144 of driving head 140 has apertures 152formed therethrough. Apertures 152 are appropriately sized so as toslidingly receive penetrators or pilot needles 154, 156 and may be boredirectly into the material of anvil portion 144 or may be lined with ametal guide tube or the like inserted into a bore in anvil portion 144.Pilot needles 154, 156 have a generally arcuate shaped cross-sectionthroughout distal portions 155, 157, and a solid cylindricalcross-section in proximal portions 159, 161. Each distal portion 155,157 has an inner concave surface 158, 160 for accommodating andretaining a fastener 400, and each proximal portion 159, 161 engages theback surface of the fastener 400, allowing the fastener to be advanceddistally with the needles. The distal ends 162, 164 of pilot needles154, 156 have a sharp point for penetrating skin. Pilot needles 154, 156are vertically disposed at a distance d1 below top surface 166 of anvilportion 142. It is preferably that top surface 166 be usable as areference datum for visually gauging whether pilot needles 154, 156 arelocated within target tissue zone 70. Accordingly, it is preferable thatdistance d1 be between 0.1 mm and 2.0 mm, and most preferably between0.2 mm and 0.8 mm, so that when top surface 166 is aligned with theouter skin surface, pilot needles 154, 156 are located within targettissue zone 70 and most preferably within most preferred area 72.

Delivery mechanism 128 serves to eject a fastener from driving head 140.In a preferred embodiment, slide block 122 is slidably mounted on guides124, 126, within lower handle portion 120. Slide block 122 is engagedwith trigger 200 so that actuation of the trigger causes slidingmovement of slide block 122. Pilot needles 154, 156 are fixedly attachedto slide block 122, and extend outwardly through backing portion 144 ofdriving head 140 through slot 168. Thus, back and forth sliding motionof slide block 122 causes pilot needles 154, 156 to be extended andretracted from slot 168, gap 148 and apertures 152. It will beunderstood that any number of mechanical driving arrangements can beused to impart the necessary force to pilot needles 154, 156, oralternatively to the fastener 400 directly. Examples include slidingmechanisms, cam mechanisms, spring-operated mechanisms, screw drives,pneumatic drives, automated motion control drives, or the like.

Pilot needles 154, 156 are preferably spaced apart by an interneedledistance of between about 2.0 mm and 20 mm and most preferably betweenabout 4.0 mm and 16.0 mm, so that when the driving head in placed withina skin opening to be fastened, and with the skin opening aligned withthe approximate midpoint between the pilot needles, the pilot needleswill be located within the width orientation of the target tissue zone70.

Although single fasteners may be inserted manually one-by-one betweenpilot needles 154, 156, an alternative embodiment of applicator assembly100, shown in phantom in FIGS. 14-16 has an automated fastener deliveryand storage mechanism 220. In this mechanism, fasteners are preferablystacked vertically in echelon fashion surrounding a guide member 224,and are biased downwardly with a resilient member such as a spring (notshown). Housing 222 is provided to protect the mechanism. Thebottom-most fastener in the echelon is engaged with pilot needles 154,156. As each fastener 400 is emplaced in the skin through operation ofthe applicator assembly 100 as described herein, and slide block 122 isreturned to the proximal limit of travel, the downward bias of theechelon causes the immediately vertical adjacent fastener to movedownward and become engaged within pilot needles 154, 156. The nextfastener may then be emplaced in the skin, and the process repeated.Again, it will be appreciated that numerous arrangements andconfigurations for providing and deploying multiple fasteners within thecontext of the present invention could be used, such as inline stackingin either a horizontal or vertical orientation, side-by-side stacking,rotational presentation via a circular chamber or magazine or belt ortape-attached presentation of the fasteners 400.

In FIGS. 17 and 18, there is shown a preferred embodiment of the tissuemanipulator assembly 300 of the present invention. The proximal ends 307of arms 302, 304 are joined together at fulcrum 306, forming thetweezer-like structure of the overall assembly. Gripping areas 312 areprovided on each arm to allow gripping of the assembly with the fingers.Any suitable fastening method may be used at fulcrum 306, includingrivets 316 as shown, or the arms 302, 304 may be welded, cast, or moldedtogether or may otherwise be integrally formed together. The materialand overall dimensions for arms 302, 304 are selected so as to allow thearms to be resiliently compressed inwardly with the fingers, and with amemory characteristic for returning to the original position upon theremoval of pressure. In addition, the material used for the arms andother portions of the assembly are preferably thermally and chemicallystable so as to allow sterilization with either heat or chemical means.The preferred material for arms 302, 304 is stainless steel.

At the distal ends 309 of each arm 302, 304 are formed tissuemanipulator surfaces 318. Manipulator surfaces 318 are preferablysemi-cylindrically shaped as shown, with the diametrical dimension ofeach semi-cylinder selected so as to conform to the diameter and shapeof the concave areas 150 of applicator assembly 100. Skin gripping jawmembers 314 are preferably attached to the exterior surfaces 326 of eacharm member 302, 304. Each jaw member 314 has a backing portion 324 forattaching to the arms, and a pair of inwardly directed projections 320disposed on both sides of manipulator surfaces 318. Directly opposedserrations 322 are preferably provided on the inward-most edge of eachprojection 320 for better skin purchase. Backing member 324 may beattached to each arm 302, 304 using any suitable attachment method,including mechanical fasteners such as the rivets 316 as shown. Forreasons that will be further explained, it is preferable that each jawmember 314 is of sufficient resilience and is attached so that inwardlydirected projections 320 may deflect separately from skin manipulatorsurfaces 318 under moderate finger pressure applied to arms 302, 304.This may be achieved through concerted selection of the material usedfor jaw member 314, the thickness dimension of backing member 324, andthe free length L1 of each backing member 324 between the inwardlydirected projections 320 and the fastener 316 closest to the distal end309 of the arm. The objective of the design of the backing member 324 isto have the jaw members 314 engage tissue with a first force and havethe manipulator surfaces 318 engage tissue between the jaw members 314with a second force that is greater than the first force. In addition,the use of a pair of directed projections 320 on each side of thevertical interface 51 serves to stabilize the tissue laterally betweenthe pair of projections 320.

Mechanical stops 330 are provided to prevent pressure beyond thatnecessary to ensure optimal approximation of tissue into gap 148 andconcave portions 150 of applicator assembly 100 from being transmittedthrough manipulator surfaces 318. Preferably, mechanical stops 330 areset so that manipulator surfaces 318 close to a distance that is spacedapart from the inter-needle distance of pilot needles 154, 156 by arange of 0.2-0.8 millimeters, such that the total distance betweenmechanical stops 330 is 0.4-1.6 millimeters greater than theinter-needle distance between pilot needles 154, 156. In a preferredembodiment in which the interneedle distance is set at 3.25 millimeter,the mechanical stops 330 would allow the surfaces 318 to close to withina range of 3.65-4.85 millimeters when approximating tissue into gap 148.Although jaw members 314 may be formed from any suitable material, thepreferable material is stainless steel.

In FIGS. 19 and 20 there is shown a preferred embodiment of a fastener400 of the present invention. Fastener 400 has body portion 402, whichcomprises a cross-member 408 connecting a pair of fork members or legs406. The outer margins 410 of each leg 406 are dimensioned and shapedaccommodatingly to the inner concave surfaces 158, 160, of pilot needles154, 156, allowing fastener 400 to fit and slide between the distalportions 155, 157 of the needles, as is shown best in FIGS. 12 and 13.Shoulders 414 preferably are provided to engage the solid cylindricalcross-section of the proximal portions 159, 161 of pilot needles 154,156, thus allowing fastener 400 to be advanced distally with motion ofthe needles. The distal end 412 of each leg 406 is incurvately shaped toallow easier passage through an opening in skin, referred to as a skive,that is created by pilot needles 154, 156. Inwardly directed barbs 404preferably are provided on each leg 406 to resist withdrawal of thefastener once emplaced.

Although an overall U-shape for the fastener 400, as shown in FIGS. 19and 20 is preferred, other shapes having a capability for bilateraltissue engagement are also possible and within the scope of theinvention. Such other shapes include for example, but are not limitedto, a square shape similar to an ordinary staple, a semi-circular orC-shape or a V-shape or W-shape in which the cross-member 408 has bendsor other features. While the shape of fastener 400 is generallydetermined in a planar configuration, it will be recognized that othernon-planar shapes and configuration can be used, such as a fastenerhaving multiple projections for each leg 406, with each projectionoriented in a different plane, or a fastener having cross-member 408arranged in a V-shape projecting out of the normal plane of the fastener400. Two leg members 406 are preferred, but it will be understood thatadditional leg members 406 could be added in the same or a differentplane of the fastener 400 such that the leg members of each side of thefastener form a dident or trident configuration, for example.

As shown in FIG. 39, an inner cross-sectional area 409 is defined by thefastener 400 for capturing the compressed dermal tissue. In a preferredembodiment, inner cross-sectional area 409 ranges from 1.5 sq. mm to 50sq. mm and most preferably about 5 sq. mm to 10 sq. mm. This area isgenerally defined by an inner diameter length of between 1.5 mm and 9 mmand most preferably about 3.8 mm and an inner diameter width of between1 mm and 5 mm and most preferably about 2 mm. It will be apparent thatnumerous shapes and configurations can be used for the shape andarrangement of cross-sectional area 409. Preferably, innercross-sectional area 409 is generally arrowhead shaped as a result ofthe positioning of the barbs 412. As will be described, the barbs 412 orsimilar anti-reversing projections resist against the withdrawal offastener 400. While the barbs 412 are preferably oriented into the innercross-sectional area 409, it will be appreciated that barbs 412 may beomitted or may be oriented outwardly.

Although it is possible for fastener 400 to be deformed during deliveryand application, preferably the majority of dermal tissue retainedwithin cross-sectional area 409 is captured in a compressed state by afastener 400 that is sufficiently rigid so as to retain the dimensionalintegrity of cross-sectional area 409 within +/−30% of its designed areafor a period of preferably at least 10 days. Most preferably, structuralintegrity of fastener 400 is maintained for at least 21 days. In thisway, the dermal tissue captured in fastener 400 is retained in acompressed state for a period sufficient to allow the biological healingprocess to occur without the dermal tissue being under tension duringthe healing process. Preferably, the dimensions of the fastener 400 andthe operation of the applicator assembly 100 coordinate to create acompression ratio of dermal tissue within the inner cross-sectional area409 that is greater than one. The compression ratio is defined either asa ratio of area or a ratio of width. In the case of width, thecompression ratio is the ratio of the dimension defined by the positionof the skive relative to the vertical interface 51 when the dermaltissue is at rest divided by the position of the skive relative to thevertical interface as held by the fastener 400. In the case of area, thecompression ratio is the ratio of the area of dermal tissue that will beretained by the fastener 400 when that dermal tissue is at rest dividedby the actual cross-sectional area 409.

Alternatively, it is possible to take advantage of the bilateral tissuefastening in the tissue target zone as taught by the present inventionwith a deformable fastener where the deforming of a bioresorbable orbioabsorbable fastener serves to provide at least some of thecompression of the dermal tissue such that the need for a mechanicaltissue manipulator is reduced or potentially eliminated. In thisembodiment, a bioresorbable or bioabsorbable fastener would be deformedby the applicator apparatus in order to appropriately compress thedermal tissue. Deformation of a bioresorbable or bioabsorbable fastenercould be accomplished in a number of ways, including prestressing thefastener into an open configuration such that it returns to a closedconfiguration, with or without mechanical assistance from theapplicator, application of ultrasound, heat or light energy to alter theshape of, or reduce or relax stresses in, the fastener in situ,designing a polymer material with appropriate shapes and compositionsthat the material is deformable upon deployment without fracturing, orany combination of these techniques.

Fastener 400 is preferably formed from any suitable biodegradablematerial. The currently most preferred biodegradable material is alactide/glycolide copolymer where the ratio is never less than at least10% of one element and preferably in a range of 60%-70% lactide.Examples of other suitable materials include poly(d1-lactide),poly(1-lactide), polyglycolide, poly(dioxanone),poly(glycolide-co-trimethylene carbonate), poly(1-lactide-co-glycolide),poly(d1-lactide-co-glycolide), poly(1-lactide-co-d1-lactide) andpoly(glycolide-co-trimethylene carbonate-co-dioxanone). In addition,other suitable materials could include compositions with naturallyoccurring biopolymers such as collagen and elastin, or stainless steel,metal, nylon or any other biocompatible materials in the case of anon-absorbable fastener, or even various combinations of such materialsdepending upon the desired application and performance of the fastener.

With reference to FIGS. 21-24, the operation of the apparatus of thepresent invention may now be explained and understood. A fastener 400 isfirst loaded between pilot needles 154, 156, as shown in FIG. 12. Slideblock 122 is then proximally retracted to the fullest extent so thatpilot needles 154, 156 and the fastener 400 are entirely within slot168. Driving head 140 is then introduced into skin opening 50 and topsurface 282 is aligned with the outer surface of the skin as shown inFIG. 21. Tissue manipulator assembly 300 is placed with jaw members 314on either side of driving head 140. Arms 302, 304 of manipulatorassembly 300 are pressed inward so that jaws 314 engage the skin surfaceand begin to force the skin 52 into gap 148 in applicator assembly 100as shown in FIG. 22. Serrations 322 provide purchase on the skin surfaceand prevent lateral slipping of the skin relative to the jaws. Asfurther inward pressure is applied to arms 302, 304, inwardly directedprojections 320 engage side surfaces 170 of anvil portion 142 and sidesurfaces 172 of backing portion 144, each with a single thickness ofskin trapped between as shown in FIG. 23. Still further inward pressureon arms 302, 304, as shown in FIG. 24, causes tissue manipulatorsurfaces to deflect inward slightly from jaws 314, until each engagesconcave area 150 of cross-member 146 with a layer of skin trapped inbetween. In this position, inner surfaces 60 of dermal layer 56 are indirect contact with each other within gap 148 and substantially parallelwith vertical interface 51, but are not overlapped or interdigitated.

In this preferred embodiment, pilot needles 154, 156 are alignedgenerally horizontally and substantially parallel with the outer surfaceof the skin and are within target tissue zone 70. Cross-member 408 offastener 400 is positioned generally transverse to vertical interface 51and a working plane of fastener 400 defined by cross-member 408 and legs406 is generally horizontal in orientation. Trigger 280 is thenactuated, causing slide block 122 to move proximally within lower handleportion 120, and advancing pilot needles 154, 156 into the skin,creating a skive through the target tissue zone 70 of the skin on eachside of vertical interface 51. Fastener 400 moves with pilot needles154, 156, and each leg 406 of the fastener 400 is simultaneously driveninto and through the skive. Once fastener 400 is advanced distally asufficient distance so that barb tips 416 of fastener 400 enterapertures 152 and accordingly emerge from the skive, trigger 280 may bereversed so that slide block 122 moves proximally, retracting pilotneedles 154, 156. Barbs 412 engage the skin, thereby preventing fastener400 from being withdrawn with the pilot needles. Once slide block 122has been fully retracted proximally, thereby causing pilot needles 154,156 to be fully retracted from gap 148, the pressure on manipulatorassembly 300 may be released and applicator assembly 100 can be movedproximally in the opening 50 to deliver another fastener 400 or can beremoved from opening 50.

In addition to the preferred embodiment of the apparatus described abovewherein the legs of a fastener are simultaneously driven through thetarget tissue zone on each side of the skin opening and with thefastener legs oriented parallel to the epidermal skin surface, those ofskill in the art will appreciate that other embodiments of a mechanicalfastening system for openings in skin tissue are within the scope of thepresent invention. For instance, the working plane of fastener 400defined by cross-member 408 and legs 406 may be oriented generallyorthogonal, or oblique in at least one orientation, to the horizontalplane generally defined by exterior surface 55 of epidermal layer 54. Insuch an embodiment, fastener 400 may be inserted in a generally verticalorientation with legs 406 pointing generally in an upward direction orin a downward direction.

Another embodiment of the apparatus of the present invention wherein afastener is driven sequentially through the bilateral target tissuezones is shown in FIGS. 25-29. In one embodiment, fastener 500 hasflexible body portion 502 with a barb 506 at distal end 505 and anattachment flap 504 at proximal end 503. Flexible body portion 502 isdimensioned so as to be received within either concave inner surface158, 160 of pilot needles 154, 156. Attachment flap 504 has slot 508formed therethrough, which is adapted to receive barb 506. In applicatorassembly 100, anvil portion 142 has concave deflector 153 formed betweenapertures 152 and extending into a portion of each aperture 152 so thatonly an area of each aperture is open sufficient to allow the arcuatecross-section of pilot needles 154, 156 to pass. In operation, and withreference to FIGS. 1-29, fastener 500 is axially aligned with pilotneedle 154, and is inserted within the corresponding concave innersurface of the needle with barb 506 oriented toward the point of theneedle. Applicator assembly 100 is then introduced into the interfaceportion 51 of the skin opening 50 as described above. Tissue manipulatorassembly 300 is then applied as before to bring the dermal layer 56 intocontact within gap 148, and thereby properly positioning target tissuezone 70. As slide block 122 and the attached pilot needles 154, 156 aremoved distally through actuation of trigger 280, fastener 500 isadvanced through the skin tissue on one side of skin opening 50 alongwith pilot needle 154 in which it is disposed. Once the tip of barb 506reaches aperture 152, however, it is engaged by, and begins to slidelaterally along, concave deflector 163, causing flexible body portion502 to bend. As pilot needles 154, 156 are further advanced, barb 506 isturned in direction 180 degrees by deflector 163. It will be appreciatedthat the barb 506 may either be positioned in front of pilot needle 154by an amount sufficient to redirect barb 506 into the opposite directionor pilot needle 154 may advance into the corresponding aperture 152 to adepth at which the redirection of barb 506 upon the entry to aperture152 will be sufficient to redirect barb 506 into the opposite direction.Once redirected and positioned in line with the second skive, barb 506is advanced in the opposite direction by pilot needle 156 and throughthe skin tissue on the opposite side of the vertical interface 51 aspilot needle 156 is withdrawn. Once barb 506 emerges from the dermaltissue, attachment flap 504 may be bent so that barb 506 may be pushedthrough slot 508, thus securing fastener 500 in a loop and bilaterallycapturing both sides of the skin opening 50. It will also be appreciatedthat attachment flap 504 may be replaced by suitable structure onflexible body 502 for engaging a suture. The suture lock of co-pendingapplication entitled “SUTURE LOCK HAVING NON-THROUGH BORE CAPTURE ZONE,”application Ser. No. 10/166,161, filed Jun. 10, 2002 which is commonlyowned by the assignee of the present invention and the disclosure ofwhich is hereby incorporated by reference, may then be used to securethe suture to barb 506, completing the bilateral capture. In thisembodiment described herein, the skives are created simultaneously andthe fastener 400 is inserted sequentially into each corresponding skivefrom an opposite direction. Alternatively, a single U-shaped needlecould be utilized in place of pilot needles 154, 156 and both the skivesand fastener could be created and inserted sequentially. Numerous othercombinations of bilateral creation of skives and insertion of fastenersare contemplated by scope of the present invention.

As described herein, the fastener is oriented so that a working planedefined by the flexible body 502 of fastener 500 is substantiallyparallel to a plane generally defined by exterior surface 55 ofepidermal layer 54, and transverse to vertical interface 51. Those ofskill in the art will appreciate, however, that the working plane offastener 500 could also be oriented substantially orthogonal, oroblique, with the plane generally defined by exterior surface 55 whileremaining in a transverse orientation with respect to vertical interface51. Those of skill in the art will also appreciate that other bilateralcapture mechanical fastening systems wherein the target tissue zones arepenetrated by a fastener in sequential fashion are possible within thescope of the present invention. For instance, a semi-circular, oval, orspiral fastener may be advanced sequentially through target tissue zones70 on each side of vertical interface 51 using a mechanism that impartsa rotational motion to the fastener, but without causing interdigitationor overlapping of skin across vertical interface 51. The mechanism mayhave means for creating a semi-circular, oval or spiral skive throughwhich the fastener may be advanced, or the fastener itself may be formedfrom sufficiently rigid material and have a sharpened point so as to becapable of creating a skive as it passes through the skin. In anotheralternative embodiment providing a sequential bilateral capture motion,a fastener is provided having a cross-member connecting two legs whereinthe legs are staggered so that when the fastener is advanced into theskin in a linear fashion, one of the legs precedes the other. In stillanother embodiment, two straight fasteners comprising a shaft portionwith skin-engaging barbs are provided. These fasteners are oriented inopposite directions on either side of the vertical interface 51, and aresequentially advanced through respective skives by an applicatorassembly allowing a reversible motion.

In one embodiment, as shown in FIG. 34, a tab or other similar guidingstructure 167 projects from an exposed portion of anvil portion 140 toserve as a reference guide to locating the external surface of the skinagainst such guiding structures. Most preferably, this guiding structure167 is adapted to mate with a corresponding pair of surface guidingfeatures 169 on the internal surface of arms 302, 304 of the tissuemanipulator assembly 300 so as to provide both a tactile and visualindication of the appropriate positioning of the applicator 100 andtissue manipulator 300 relative to the vertical interface 51 of thetissue opening 50. Preferably, the guiding structure 167 and guidingfeatures 169 combine to force the applicator 100 to stay laterallycentered about the vertical interface 51 and to stay properly positionedboth horizontally and vertically. Alternatively, visual indicatorsand/or an exterior platform-like structure around the exterior ofdriving head 140 may be provided to assist the user in properpositioning of the applicator assembly 100 and the tissue manipulatorassembly 300.

FIGS. 35 and 36 show an alternate embodiment of applicator assembly 100and tissue manipulator assembly 300 in which both manipulator surfaces318 and concave areas 150 are semi-spherically shaped to provide guidingstructure in both horizontal and vertical orientations as the tissue iscompressed by the tissue manipulator 300 into the applicator 100. Inthis embodiment, there are no inward projections 320 shown for capturingthe tissue as the application of pressure to the ball-like tips 318provides both the capture and compression forces imparted to the tissue.Areas 150 on the applicator 100 are semi-spherical in shape to mate inmore than one orientation with the ball tips 318, rather than beingmerely concave to align the tissue in a single orientation.

FIG. 37 shows another alternate embodiment of applicator assembly 100 inwhich the fasteners 400 are inserted obliquely into the tissue along thevertical interface 51. In this embodiment, the penetrating needles 152,154 are oriented obliquely downward relative to the horizontal and thedistance d1 on the driving head 140 is reduced. An upper projection 167extends on top of the vertical interface 51 of the opening 50 to serveas a guide and the aperture 141 between upper projection 167 and thedriving head 140 is positioned to require less rotational movement ofthe applicator assembly 100 in the plane of the vertical interface 51when the tissue is being positioned in the driving head 140 or theapplicator assembly 100 is being positioned for insertion of asubsequent fastener 400. One advantage of the oblique orientation of thefasteners 400 along the vertical interface 51 of opening 50 is that theeffective spacing between backing members 408 of adjacent fasteners 400is reduced, thereby affording the opportunity to increase the resultingholding pressure that can be applied across the vertical interface 51 toresist tearing by being able to insert more fasteners per longitudinaldistance of the opening 50.

FIG. 38 shows another embodiment of the present invention in which thetissue manipulator 300 and the applicator assembly 100 are integratedtogether into a single handheld surgical instrument 600. In thisembodiment, a manual trigger 200 is used to activate first the lateralcompression operation of the arms 302, 304 of the tissue manipulatorassembly 300 and then is further depressed to engage the deliverymechanism 128. A force translation mechanism 602 inside the handle 110in the form of a cam, wedge or similar arrangement is first engaged bythe depression of the trigger 200. Further depression of trigger 200then causes delivery mechanism 128 to be actuated. It will beappreciated that a single handheld surgical instrument 600 integratingthe structures of both the applicator assembly 100 and the tissuemanipulator assembly 300 could be arranged and operated in a number ofways. For example, two trigger actuators could be used instead of onetwo-stage actuator. Instead of arranging the tissue manipulator assembly300 and the applicator assembly 100 inline in the same orientation, thetwo assemblies 300 and 100 could be arranged to face each other in thelongitudinal orientation.

Although the present invention has been described with respect to thevarious embodiments, it will be understood that numerous insubstantialchanges in configuration, arrangement or appearance of the elements ofthe present invention can be made without departing from the intendedscope of the present invention. Accordingly, it is intended that thescope of the present invention be determined by the claims as set forth.

What is claimed:
 1. A mechanical method of bilaterally securing skintissue with a fastener comprising: approximating a portion of aninterior surface of each of two pieces of living dermis tissue along avertical interface that is generally perpendicular in at least oneorientation to an exterior surface defined by epidermis tissueassociated with the living dermis tissue without overlapping eitherinterior surface across the vertical interface; positioning a mechanicalapparatus having a driving head portion positioned in the verticalinterface and at least partially below the exterior surface and a handleportion positioned at least partially above the exterior surface; andutilizing the mechanical apparatus to bilaterally drive at least oneportionof the fastener through each piece of the living dermis tissuebehind the vertical interface and the interior surface of that piece oftissue such that the fastener is positioned below the exterior surfaceand a portion of the fastcner is positioned generally transverse to thevertical interface.
 2. The method of claim 1, wherein the fastenerincludes at least two leg members and a cross-member and wherein thestep of utilizing the mechanical apparatus simultaneously bilaterallydrives each of the at least two leg members through a correspondingpiece of the living dermis tissue.
 3. The method of claim 2, wherein thecross-member is the portion of the fastener positioned generallytransverse to the vertical interface and wherein the step of utilizingthe mechanical apparatus positions a working plane of the fastenerdefined by the cross-member and two leg members in a horizontalorientation generally parallel in at least one orientation to theexterior surface defined by epidermis tissue.
 4. The method of claim 1,wherein the fastener includes a portion configurable in a generallyU-shaped configuration and wherein the step of utilizing the mechanicalapparatus sequentially bilaterally drives the fastener first through oneof the pieces of living dermis tissue and then through another of thepieces of living dermis tissue.
 5. A mechanical method of bilateralfastening of opposing skin tissue across an opening comprising:utilizilig a manipulator apparatus to position the opposing tissuetogether such that dermal layers are proximate each other at the openingand a pair of spaced apart target tissue zones are presented to afastening apparatus, each target tissue zone being defined in a plane ofeach epidermal layer generally perpendicular to both a surface of theassociated epidermal layer and a longitudinal orientation of theopening; utilizing the fastening apparatus to bilaterally secure thedermal layers by inserting a fastener through each of the target tissuezones while opposing tissue is positioned together in an orientationgenerally perpendicular to the plane of the target tissue zones.
 6. Themethod of claim 5, wherein each target tissue zone is defined in theplane by a rectangle of dimensions less than or equal to 2 mm deep byless than or equal to 20 mm wide on opposite sides of the longitudinalorientation of the opening and at least 0.1 mm below the surface of theassociated epidermal layer.
 7. The method of claim 6, wherein therectangle has dimensions of 1 mm deep by 10 mm wide.
 8. A mechanicalmethod of fastening of a pair of opposing pieces of skin tissue across agap comprising: utilizing a mechanical apparatus to position a dermallayer of each of the opposing skin tissue together at the gap such thata pair of unique tissue target zones in the dermal layer are presented,each tissue target zone being defined in a three dimensional volume ofone of the pieces of opposing skin tissue at a depth of between 0.1 mmand 2.0 mm below an exterior surface of the skin tissue, at a width ofbetween 1 mm and 20 mm from an edge of the gap and along a longitudinallength of the gap wherein the depth and width define an insertion planegenerally perpendicular to the longitudinal length of the gap; utilizinga fastening apparatus to secure the dermal layers by inserting a portionof a fastener through the insertion plane into each tissue target zonewhile the opposing tissue is together with no portion of the fastenerabove the exterior surface of the skin tissue.
 9. The method of claim 8,wherein the fastener is inserted in each tissue target zone in agenerally horizontal orientation parallel to the exterior surface of theskin tissue.
 10. The method of claim 8, wherein the fastener is insertedin each tissue target zone in a generally oblique orientation andparallel to the exterior surface of the skin tissue.